Whilst I would say that triggering an Economic Crisis in the US which spreads to other Economies is a greater risk than a World War, American Presidents starting wars to distract from their own mismanagement is tradition and given Trump's "if some is good, the maximum possible is the bestest" philosphy in his policy choices so far in this presidency, him through an accumulation of measures that make enemies out of friends, and small military interventions creating a situation that escalates to WWIII, is a realistic possibility.
I mean the idea that the threat of Military Force is a valid tool even against US Allies predates Trump - just look at the Legislation Congress passed to invade The Netherlands if ever an American national was arrested by the ICC - and Fascists traditionally see Military Force as a perfect valid tool in the Great Game and Allies as only good as long as they're useful.
Considering just how many Americans voted for him and the brainwashed hyper-nationalism that's the bread and butter of military training everywhere, I wouldn't rely on the US Army to not go ahead and attack a target in a country that was deemed a US Ally just months earlier and something like that escalating to something much bigger.
That would be a correct assumption about 3 months into that invasion.
All it takes to disprove that idea right now is to listen to what Macron has been saying, and the guy is a Hard-right Neoliberal whose government is supported by the French Front-Nationale (France's main Far Right party).
By now most of the energetic transition in Europe is either done or the money for it is already invested (with temporary measures in place until the things being built with that money come online), and Europe is already over the peak economic impact point of weaning itself from Russian fossil fuels.
Further, a lot of the forced transition away from Russian fossil fuels was to energy sources which are cheaper or well on their way to become cheaper than fossil fuels, such as electricity from renewable sources. That transition just hadn't happenned before because it costs a good amount money to merelly do the change and people, companies and governments were content to keep on paying just a bit more for Russian gas than for Renewables to avoid paying a big one off amount to transition, but by now that cost is sunk and large parts the Economy have made changes needed to transition (for example, look at how Germans have been replacing their gas house warming systems with things like heat pumps).
At this point there is very little to gain in going back to the suckling from Russia's fossil fuel tit (except perhaps for a handful of Chemical Industry Conglomerates in Germany who had massive profits from using that as inputs for many processes) and in a lot of cases it would actually be a net loss in pure Financial terms (so, if not counting the geostrategical and military risks of giving money to Russia) because the energy sources they use post-transition are already cheaper that even Russian gas and getting cheaper by the year.
Also, lets after 2 years of pretty much all of Eastern Europe as well as the likes of Finland reminding us of what Russia did to them while Russia is trying to do the same to Ukraine, Russian government politicials themselves talking about invading the rest of Europe ("from Vladivostok to Lisbon") and continued coverage of Russian missiles killing civilians in Ukraine who to Europeans "look like us", the idea of Russia as a dangerous out of control beast that Ukraine is holding off from attacking the rest of us is in the minds of the European Public in general, not just politicians, plus like in Canada, European nationalism and anti-Americanism have started ticking up in Europe in response to Trump, so just bending over to Trump and Putin and giving Russia a win in Ukraine wouldn't be a good career move for mainstream European politicians and those who might go for it - Far-Right parties in Europe - mainly get stuck at just over 20%, even in countries like The Netherlands and France where they've been present for decades, so they're not going to be in a position to work in the interests of Russia and Trump's America and if they tried to do it via public pressure, they would open themselves to accusations of being Traitors To The Nation from their very own natural supporters, fragmenting the Far-Right.
Then there's also all the extra military investment all over Europe that was started with Ukraine as a justification, which makes going back on the justification for all the money already spent and all the pro-military talk a pretty dangerous career move for any politician that did it.
But yeah, as I said at the start, had this happenned in the very beginning of the war, I agree with you that European politicians would have been relieved and just concede more of Ukrainian Sovereignty to Russia, same as they did back when Russia invaded and took Crimea from Ukraine.